Automatic train-control system



Jan. 13, 1931. w. K. HOWE AUTOMATIC TRAIN CONTROL SYSTEM Filed May 40 1918 2 Sheets-Sheet 1 A TTOfM/E V Jan. 13, 1931. w. K. HowE AUTOMATIC TRAIN CONTROL SYSTEM 2 Sheets-Sheet 2 Filed May 4I 1918 Ilm I300 [200 IIN Arron/vir y matically controlling the movement of the Patented .im is, 1931 UNITE 'E' PAT WINTHROP K. EOWE, OF ROCHESTER, vN'W YGRK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, 0F GATES, NEW YORK, A. CORPORATION 0F NEW YORK i AUTOMATIC TRAIN-CONTROL SYSTEM application mea my a, reis. serial no. aaafsoa.

This invention relates to systems for automatically controlling the movement-of railway trains or vehicles, and more articulary to such systems in which signals or the gui ance of t e engineer or motorman of the train are operated or displayed in his cab, and in which suitable provisions are made for antotrain whenever the engineer fails to proporly observe the signals and control his train in a way consistentwith safety.

It has heretofore been recognized that the well known block signaling systems using fixed signals do not afford all the safety Iand rotection desired, because actual tria emonstrated that serious accidents sometimes occur becausethe engineer is unable to read these signals correctly, or negligently fails to` do so, or for some reason fails to obey these signals. It has been proposed to provide mechanical devices for automatically Governing the movement of a train under tdangerous conditions, in order that an accident may be prevented in case the engineer fails for any reason to properly control his train himself. It is appreciated, however, that mechanical devices, as well as the human element, are liable to failure at critical times,

and in order to obtain the best and mosty effective results, it i's preferable to use the automatic mechanical devices more to supplement the vigilance of the engineer, than as the principal `and only safeguard, so that before accident can occur, it is necessary for both the engineer and the mechanical devices to fail to'perform their proper duties. To attain this endit is necessary as a practical consideration to adopt some way of preventing the engineer from becoming careless or negligent and relying upon the mechanical devices with which his train is equipped, otherwise safety would in realitybe dependent on the reliability of the mechanical devices. This may be accomplished by making ita practice to impose severe penalties upon the engineer in everyv instance where he has been so careless or negligent that the automaticmechanical devices have acted to control the train because of his failure to do so. Before such penalties can be imposed, however, it is necessary to furnish the engineer with ample information as to lwhen and how vhe shouldcontrol his train and also to provide a reliable and accurate recordin device or similar mechanism who will etect the failure of the engineer to performhis duties properly.

With these considerations in view, one of the objects of this invention is to provide a reliable and accurate warning signal-in connection with automatic train controlA apparatu's, which will give to the engineer a readily recognized signal, warning him of the existence of danger and further advising him 'that unless he shall promptly slow down his 'f Itrain by his own initiative, the automatic train control apparatus will operate.

further object of the invention is to provide suitable means whereby the warning signal will be given for a time prior t0 the automatic application of the brakes by the train control apparatus which is suliicient to permit the engineerto take appropriate action toward slowing down the train himself, vrnd further to provide suitable means so that when the engineer acts properly in obedience to the warning signal, and there is no necessity for the automatic train'control apparatus to operate, the operation of this apparatus will be automatically prevented.

A still further object of this invention `is toprovide for the giving of a warning signal prior to an automatic application of the brakes by the operation of the train control .apparatus in such a way and under such circumstances as will govern the train with the necessary safety and without unnecessarily delayingl its movements,jthereby affording' shoes.

gineer has tailed to properly perform his duties.

Further object-s and advantages of the invention will be readily apparent as the description of the invention progresses. In describing the invention 1n detail, ref erence will be made to the accompanying drawing, in which is illustrated a preferred embodiment of my invention, in which like reference characters designate corresponding parts in the several views, and in which:

Fig. 1 is a diagrammatic view, partly in the nature of a wiring diagram, which illustrates in a simplified form the parts and circuits on the vehicle which constitute one speciic embodimentl of this invention, said parts and circuits being illustrated more with the view of making their functions and opera tions more readily understood than with regard to their exact construction and arrangement;

Figs.. 2 and 3 are schematic diagrams showing the closed position of certain contacts used in the embodiment of the invention shown; l

Fig. 4- is a diagrammatic view showing one arrangement of the parts and circuits ci the system along the traclr; and

Fig. 5 is a diagrammatic view showing speed and distance curves ier illustrating the performance of trains governed by the train.

control system embodying this invention.

Referring first to the apparatus on the vehicleshown in Fig.v 1, the numerals 1 and 2 designate portions of the track rails of an ordinary railway track. The vehicle is illustrated in a simplified and conventional manner as comprising two pairs of wheels 3--3 and 4 4 connected by the usual axles 5 and 6. The frame of the vehicle or train is shown in a simplied manner as formed of two side bars 7.

According to the specilic embodiment oi the invention illustrated, communication between t-he track and the vehicle, necessary for the control of the automatic apparatus on the vehicle in accordance with trac conditions, is obtained by means of ramps and Contact These contact shoes may be of any suitable construction, but in the accompanying drawing there is shown a simplified t pe which comprises a verticaily movablep ungerS slidably mounted in one of the side bars 7, this side bar for simplicity being lassdirnedto be made of wood or other similar material, in order that the plunger 8 of the Contact shoe may be insulated. The plunger 8 is pressed downward toward` its lower position (shown in Fig. 1) by a compression spring 9 interposed between the sidebar 7 and a collar 10 fixed to said piunger.: rihe plonger 8 is intended to open acircuit when lifted by its engagement with a ramp, and while this function may be accomplished 1n varier-is ways, plunger is shown as prometiera vided with a button 11 of insulating material, which is larger than the plunger so as to form a stop for limiting the downward movement thereof. This bu 'ton 11 is arranged to lift a contact spring 12 out of electrical con tact with a contact piece 13, said springv 12 and contact piece 13 beiner secured to the side bar 7. kIn korder to avoid complication, only one contact shoe on one side of thevehicle has been illustrated, but it is contemplated that in practice a contact shoe will be located on each side of the vehcle so that the desired cooperation of a contact shoe with the ramps along the track will occur regardless of which way the vehicle is headed.

T he ramps may be of any suitable construction and in general comprise metallic contacting portions having sloping ends which are lined in any suitable manner adjacent to one of the track rails but insulated therefrom so as to be in position to be engaged by the plunger 8 of the contact shoe of each train or vehicle. These 1amps, being well known in the art, are illustrated conventionally in the drawing and are designated by the reterence character lt. Associated with each ramp lt is a source of electrical energy and Vbe described hereinafter; but in Fig. l, the

source of current is shown as a transformer T, having one terminal of its secondary connected to the ramp R. The secondar of this transformer is provided with two taps, giving diiierent voltages, and by means of a switch 14- either of these two taps may be connected to the track rail 2. It is apparent that the simpliiied arrangement shown in Fig. 1 provides for connecting the entire voltage of the secondary of the transformer T across the tracl rail 2 of the ramp R, for connecting the voltage ot only a part ot' this secondary across the `rack rail and ramp, and for disconnectingthe secondary entirely. For convenience, these different electrical conditions of the ramp R will be hereinafter termed high voltage on' the ramp, low voltage on the ramp, and zero voltage on theramp, respectively. While in some instances the voltage applied to a ramp R may be controlled manually by a switch 14, ordinarily in practice the electrical connections for these different voltages are governed automatically in accordance with trafhc Aconditions, as shown in Fig. 4.

rlhe simplified form of a. train control apparatus shown in Fig. 1 comprises a worm 15 fined to the axle 6 and meshing with the worm wheel 16 secured to the lower end of a shaft 17 which is supported by suitable ,fixed supports 18. The shaft 17 drives. a suitable speed responsive device which serves to indicate or establish, by the degree of lili movement given toa movable ,part or meni-v ber, `the actual-speedat which the train; iS."

traveling at any time.y illustrated, this speed responsive device` comprises a block 19 `fastened tothe shaft 17, .and a movable block 20 loosely mounted on said shaft 'seas' to. slide lengthwise thereon.; Arms'2l carrying weights at their lower ends: are pivotally Vconnected to the fixediblock'lt) at their upper ends, and links-22V are connected vbetween these arms andthe lowerjmovablefblock 20.

- Between the blocks 191'and 20 is interposeda compression spring V23.` The block 20 is formed with anges j 24,V .between l which are disposed rollers 2 5 carried by! the 'bifurcated end of a lever 26, onlyoneof .saidrollers'v being shown., v The operation of :this speed responsive ldevice is'similar to that of the tion.

other wlth-relationto the. gear 27. Each of the gears 28 is providedwith clutch teeth adapted to engage corresponding teeth formedin the ends cfa slidable sleeve 30,.

which'is mounted on'the shaft 29 between the two bevel gears 28 and which is connected to Vthe shaft 29 by a pin and slot connection 31'.

i The construction of parts just described con- Vstitutes one form of an automatic reversing gearing: The voperation of .thls reversing gearing will be apparent without further vexplanation and is used for the lpurpose 'of causing the shaft 29 to rotate in the same .direction regardless of which directionithe shaft l17 is rotated, so that Whichever way jthe vehicle is headed, the shaft 29 is always rotated in the same direction.

The shaft 29 issupported in suitable fixed supports 32 and is connected by a universal coupling 33 to another shaft 34. Dis osed above'the `outer orfree end of the sha t 34, is a cam control solenoid 35, having a core 36 which -is pivotally connected toa sleeve- 37 loosely mountedon theshaft 34. Secured to the shaft 34 is a worm 38 which is adapted to `mesh with a worm wheel 39 fixed to a cam for limiting the movement of the cam K unf der the iniiuence of the counterweight 42. When the shaft 34 is allowed to drop by its end of. k17 is' secured with'thev worm gear 39,and the-cam-shaft 40 p and the cam K are gradually turned in accordance with the distance traveled by the ve- From the construction so fardescribed, it can be seenthat a movablepart, namely the block 20 of thespeed responsive device, is caused to assume .differentpositions' in accordance with variations in the actual speed of the vehicle, yand that another movable part, namely, the cam K, is caused to be raduallymoved attimes in accordance wit the distance traveledby the vehicle so that its follower is moved to establish varying permissive.` speeds for the vehicleat diderent points in its travel, the variationm the permissive speeds-being determinedby the shape of this cam. Thus, there is provided automatic means for determining the desired permissive speed for the vehicle and also its'actual speed, and in order 'to obtain the automatic control desired, it remains to compare theactual speed with the existantpermissive speedby suitable mechanical devices and arrange tocontrol thefmovement of the vehicle'when its' actual speed exceeds the desired permissive speed. In the simplified construction illustrated, the iioating lever 26 is connected at one end bythe rollers 25 and own weight, upon deenergization of the sole- Vvnoid 35, the worm 38 is brought into meshv the flanges 24 to the block 20 of the speed perl missive device,"and this lever carries at itsv other end a freely revoluble roller 44 which bears against the edge of the camk K. Pivotally' connected tothe lever 26between its ends is a link or member 45 Which'is pulled downward by a spring 4 6, this springserving to press' the roller 44 against the edge of '.thecam K. Fastened to the link 45 is a piece of insulating material 47 `which is arranged, when the link 45 has been raised to a predetermined extent, to move a lcontact member 48 upward away from one contact (indicated'conventionally by an arrow) against another contact, thereby controlling circuits for the purpose hereinafter explained.

The train .control apparatus hereinbefore described is controlled so as to have its operation initiated when dangerous traiiic conditions exist ahead, and to be restored to itsA normal conditions when traiiic conditions ahead become safe. The vappropriate control of this train control apparatus is attained by the cooperation of the -trackway circuits shown in Fig. 4 and hereinafter described with suitable control devices on the vehicle. In the particular embodiment of the invention illustrated, these control devices comprise a speed control relay SC, responsive to direct current, and .a 'pck-up relay CP, re# sponsive to alternating current only. These relays SC and CP are provided withcontact fingers and associated contacts which are illustrated conventionally. The circuits corrtrolling these relays will be pointed outl hereinafter in the description of the operation.

The information furnished to the engineer or motorman for guiding him in controlling his train properly, is given by suitable cab signals which are preferably located in the engineers cab and which are so constructed as to give arrestive and readily distinguishable indications. Asl illustrated, these cab signals comprise a proceed signal, shown as a green light G; a caution signal, shown as a yellow light Y; and a warning signal, shown as a-whistle W. The whistle W is operated by air pressure derived from a suitable source, as the main reservoir 49, and the operation of this whistle W is controlled by a piston valve 50, having a casing 51. This casing 51 is connected to the suppl reservoir 49 by a pipe 52, and t'o the whist e W by a passageway 53. The valve 50 is operated by a solenoid 54. In the construction illustrated, this solenoid 54 is normally deenergized, and the valve 50 is maintained by its own weight (aided by a spring, if necessary) in the lower osition, thereby cutting of.' the supply of air groin the reservoir 49 to the whistle W. When the solenoid 54 is energized, its core is attracted and the valve 50 is raised to open communications from the reservoir 49 to the passage 53, thereby sounding the whistle W. Fastened to but 'insulated from the core of the solenoid 54 is a. contact disk 55 which is adapted to electrically connect cooperating contacts (illustrated conventionally by arrows) when the core is attracted, .for the purpose hereinafter explained.-

Associated with the train control apparatus and forming'an important part of this invention, is a slow-acting circuit controlling device P, adapted to be operated electrically. According to the embodiment of the invention illustrated, this device P is shown in a simplified form as controlled in accordance with time, and comprises a solenoid'M having two windings 57 and` 58 and a vertically movable core 59. Secured to the core 59 and insulated therefrom are two contactdisks() and 61; The contact.` disk 60 is arranged toe establish an electrical connection between its cooperating contacts (illustrated conventionally as arrows) after the core 59 has moved downward to its lowermost position.

The contact disk 61 is arranged to establish electrical connection between its cooperating contacts, when the core 59 is in its upper position andduring the movementy of said core nearly to its lower position, the Contact diskl 61 breaking circuit at the same time or slightlly after the contact disk makes circuit.

he downward movement of the core 59 is retarded gradually in accordance with time by a suitable time controlled device. ,In the particular simplified construction illustrated, a piston 62 with a flexible packing is fastened to the lower end of the core 59, and this piston noid 69.

According to the embodiment of the inven-I tion illustrated, it is contemplated that the movement of the train or vehicle will be retarded by the well-known system of air brakes, and since this system of brakes is well known, it is only necessary to illustrate generally how the parts of the train control system act to cause an automaticapplication of the brakes. A portion of the train pipe forming part of the air brake system is shown and designated 65. As is well understood, the venting of this train pipe causes an automatic application of the brakes, either a service or an emergency application, depending upon `the rapidity with which the air is vented.

For automatically venting this train. pipe so as to cause an automatic application of the brakes, an electro-pneumatic valve E. P. V. is connected to this train pipe. As shown, this valve E. P. V. comprises a casing 66, and a valve proper 67, which is urged by aspring 68 to its open position and which is held against the opposition of said spring in its closed position` by a-normally energized sole- The instrument for recording or indicating when the train control apparatus has acted .automatically to cause an `application of the brakes, because of the failure of the engineer to properly control his train, may take various forms;Y This instrument is illustrated conventionally in the drawing as a recorder orcounter I which is adapted to be operated upon energization of an electro-magnet or solenoid 70. It is contemplated that in practice this recorder I will be encased and sealed in some appropriate manner, so that it may be inspected by authorized persons but cannot be maliciouslyV manipulated by the engineer.

According to the embodiment of the invention illustrated, it is assumed that the power used to propel the vehicle is electricity, which is controlled in the usual way by a controller L (shown diagrammatically) It should be understood, however, that by modifications readily apparent to the ordinary mechanic, this invention may be applied to trains which are propelled by steam. The controller L is provided with a suitable circuit controlling device, adapted to lclose a breakin .a circuit when the controller is in its off position and also to close a break in another circuit when the controller is in any one of its several positions in which the power is on. As shown, this circuit controller comprises a drum 71 of suitable insulating material, which is operatively connected to the handle 72 of the controller. This drum 71 carries a contact strip 73, and carried by suitable insulating supports are two pairs of contactingers c and d. The construction anov arrangement of these parts is such that when the controller l1andle 72 is in its off position the contact fingers c are bridged by contact strip 73, whereas the contactingers (Z are bridged by the contact strip 73 when the controller is moved to any one of itsv power positions. This range of control of these pairs of contacts is shown diagrammatically in Fig. 3.

The usual enginccrs brake valve by means of which he controls the automatic application and release of the air brakes is shown diagrammatically and designated H. Operatively connected to this brake valve is a drum 74 of suitable insulating material. to

which is fastened a contact strip 75. As is well known, the handle of the engineers brake valve has several different positions, commonly termed release, running, lap, service and emergency. Associated with the contact strip 75 is a pair of Contact iingers a which are arranged to be electrically connected by this contact strip when the handle of the engineers brake valve is in either the release or running position; and in a similar way a pair of contact fingers b are electrically connected when the handle is in either the service or emergency positions. The range of contact of the contact fingers a and is shown diagrammatically in Fig. 2.

In connection with this invention it is desirable to provide an automatic circuit controller which will be closed whenever the air brakes on the vehicle are actually applied.

l This circuit controller may be connected in various ways to the brake rigging; but as shown, this circuit controller comprises a pair of contact springs 76 secured to blocks of insulating material 7 7'fastened to a cylinder 78. Within this cylinder 78 is an airtight piston 79 which is pressed by a spring 80 toward the left (as viewed in the drawing) and which carries a contact piece 81,

said contact piece being adapted to electrically connect the springs 7 6 when the piston 79 is urged outward to the right against the opposition of the spring 80. The cylinder 78 ris connected by a pipe 82 to the usual brake cylinder 83. It will be readily apparent that when the air brakes are applied, air under pressure from the brake cylinder 83 will cause the piston 79 to move to the right and establish an electrical connection between the Contact springs 76 for the purpose hereinafter explained.

Operation Operation of speed control apparatus.- Prior to describing the operation of the system as a whole, including the trackway circuits, a brief explanation will be given of the operation of the apparatus on the vehicle which occurs when the vehicle passes a ramp at the entrance to a block when said ramp 1sl deenergized on account of the block ahead being occupied by another train. Normally the parts of the train control apparatus are in the position shown in Fig. 1, and except for the limitation upon the maximum speed at which the train may travel as explained hereinafter,the train may travel at any speed. With the parts in the normal position the speed control relay SC is energized by a circuit which may be traced as follows: Commencing at the battery 0, conductors 84 and 85, relay SC, conductors 86 and 87, contact linger 88 raised, conductor 89, contact spring 12, contact piece 13, and conductors 90, 91 and 92 back to the battery O.

When the Vehicle passes a deenergized CP, and consequently all of the contact iin rs of the speed control relay SC drop to t eir lower posit-ion. y

The dropping of the contact finger 93 interrupts the circuit which normally energizes the cam control solenoid 35, said circuit being traced as follows: Commencing at the battery O, conductors 84, 94 and 95, Contact finger 93 raised, conductor 96, solenoid 35, and conductors 97, 98, 91 and 92 back to the battery O.

The dropping of the contact finger 99 inl terrupts the circuit for lighting the green lamp G, this circuit being traced as follows: Commencingat the battery O, conductors 84, 94 and 100, Contact linger 99 raised, conductor 101, lamp G, conductor 102, 103, 98, 91 and 92 back to the battery O. Atlthe same time, contact finger 99 inl its lower position establishes a circuit for lighting the yellow lamp Y, said circuit being traced as follows: commencing at the battery O, conductors 84, 94 and 100, contact finger y99 in its l lower positionconductor 104, lamp Y and conductors 105, 103, 98, 91 and 92 back to the battery O.

In this way, when the speed control relay SC is deenergized, the proceed signal given by the green lam G is extinguished, and the caution signal given by the yellow light Y is displayed. Also, the solenoid 35 is deenergized and permits the shaft 34 to drop by its own weight and bring the worm 38 into mesh with the worm gear 39, thereby commencing a gradual turning of the cam K in a clockwise direction in accordance with the distance traveled by the vehicle.

When the speed control relay SC is deenergized, its contact finger 88 opens and makes an additional break in its normally closed energizing circuit, so that after the shoe leaves the ramp and the shoe contacts close, nevertheless, the speed control relay will not be reenergized.

With the cam K connected to the wheels of the vehicle and gradually turned as the vehicle travels through the block, there conimences a gradual reduction in the permissive speed for the vehicle; and unless the actual speed of the vehicle is maintained less than this prescribed permissive speed, the tra-in. control apparatus acts automatically to iii-st sound the warning signal, and then att-cr an interval of delay, unless the enginecr himself acts to control the train, to cause .:n automatic application of the brakes, as will be more fully explained hereinafter. rlhe shape of the cam K determines the way in which the permissive speed is gradually decreased, and in general, this gradual decrease in permissive speed is preferably determined in accordance with the actual braking curve of the vehicle. In the particular type of cam illustrated, the radii correspond to speed and the angular displacement of the cam from its initial osition 4(shown in Fig. l) corresponds to t ie distance traveled by the vehicle after the cam K has commencedvto move. In short, the cam K acts mechanically to reproduce on the train, so to speak, a certain prescribed speed-distance curve which it is desired that the vehicle should observe in travelling through the block.

In order to explain more clearly the 'factors of speed and distance which determine the preferable shape of the cam K and also to oint out the features of the construction an operation of the system embodying this invention, a number of curves are shown in Fig. 5 which are drawn with regard to a certain assumed length of block and braking equipment, together with certain other assumed conditions. These curves are drawn according to the well known method of plotting curves to rectangular coordinates, the horizontal spaces or distances representing the distance along the track, and the vertical spaces various speeds. The length of the block in Fig. 5 is indicated as the space between the insulated joints 140. rhe curve drawn as a heavy line and marked cam curve in F ig. 5 is the curve from which the shape of the cam K, suitable tor governing a vehicle in this block, would be determined; and this curve shows the diierent permissive speeds for the different points in the block which would satisfy the conditions assumed.

It should be understood that the cam curve illustrated, as well as the other curves shown megeve in Fig. 5, are drawn for illustrative purposes and while effort has been made to show such curves as would be true of practical working conditions, these curves should notbe considered as precisely correct, or as the only curves which can. be employed, singe the va* y rious assumptions on which these curves are based may be varied according to the desire or volition of the one practicing the invention.

According to the preferred method of determining the shape of the cam curve there is i'irst obtained the braking data tor the braking equipment of the vehicle or train to be governed. rlthere is a substantially uniform distance within which a train or vehicle having a given braking equipment can be broughtto a stop by its brakes when travcling at a given speedA at the time the brakes are first applied. These different braking distances tor different speeds may be determined by tests; and when such data has been collected, the different braking distances for the ditlerent speeds may be plotted to forni a speed-distance curve which may be termed the braking curve for the vehicle in question. Such a braking curve is shown in Fig. 5 between the points 107 and 108 by the heavy dash line curve marked D. This curve D indicates the speeds at the di'erent points in the block at which the brakes should be applied in order that the vehicle may be brought to a predetermined lowspeed before it reaches the end of the block. iVhile this curve D may be based upon either an emergency or a service application otthe brakes, with suitable margins or modifications as desired, this curve is shown as corresponding substantiallyv with the braking curve for the vehicle under a normal service applica tion of the brakes. The distance between the point 108 and the actual end of the block, indicated by the insulated joint 140, is adopted as a margin of safety to take care ot slight variations in the braking power ot the vehicle under different conditions and slight variations in the exact point and speed at which the brakes are applied. The portion of the curve from this point 108 to the end of the block, is horizontal and indicates some arbitrary assumed low speed, such as 8 or 10 miles per hour, which is considered to a be a safe low speed for the vehicle. The horizontal portion of the curve D from the point l0? to the entrance end ott the block represents the maximum speed at which the vehicle may enter the block in question and be safely controlled by its brakes within the limits ot that block. This maximum speed is selected with due regard to the length oi the block and with reference to trackway conditions and factors affecting train capacity.

Having assumed the desired braking curve D, the cam curve is determined from this curve by making the portion otthe cam distance, is indicated bythe dotted line 106. l

braking position; and this interval of time corresponds to that for which the time control device P is adjusted to break circuit at the contact disk 61. It will be 'appreciated that this interval of timeselected should be made as short as practicable, if it is desired to obtain the best train capacity, because it is evident thatthe block may be made shorter as this time interval is decreased.

The horizontal portion of the cam curve from the point 109 to the vertical line indicating the actual entranceend of the block indicatesv the maximum permissive speed prescribed by the c am K in its normal or initial position. It will be noted that this portion of the cam curve extends a short distance into the block, indicating that the cam K does not actually commence to move until after the vehicle has traveled a short distance into the block. This delay in the be-A ginning of the movement of the cam K is due to the fact that the speed control relay SC is not deenergizeduntil after the iirst vpair of wheels of the vehicle enter the block as explained more fully hereinafter), and also because there is a slight time required for the operation of the parts which result .in causing the cam to commence to move. The delay from the instant the wheels of the vehicle first enter the block to the instant when the cam K iirst starts to move is very short when measured as time, but is appreciable when measured as distance, especially at high speeds. This interval of delay. measured as V' It will also be noted that the horizontal portion of the cam curve at the beginning end of the block is below the horizontal portion of the curve D. This diierence between the maximum permissive speed indicated'by the cam curve and the maximum speed ini dicated by the curve D- is selected with due regard to the kmaximum rate of'acce'leration of the train at this speed, so that, evenk if the vehicle were. accelerating at its maximum rate when itexceeds the maximum permissive speed prescribed by thecam,` (shown as about 38 miles per hour). the brakes would be auto# matically applied after a lapseof an interval of time before the train vcould accelerate to a speed higher'than that represented by; the

curve D. In other words, tliemaximum peu; missive speed established by the cam-iis tlonof-the devices, as hereinafter explained,

selected such that thevehiclecannot voverrun the safe brakingcurve D, under. the mostrad# verse conditions,' thereby assuring that under no circumstances will thevehicl be traveling so fast at the beginning of the block that it cannot be automatically stopped in accordance with the curve D before reaching the ond of the block. In the same way and for the same reason the lower portion of the cam curve from the point 128 to the end ofthe block is at a lower speed than the curve D, a greater difference in the speeds being shown because of the fact that as a rule vehicles can accelerate to higher speeds in a given time while traveling at a low speed than while traveling at a high speed.

From the foregoing, it can be seen that the cam curve indicates for all 'points -in the travel of the vehicle a limiting permissive speed at which the time control'd'evice P will be set'into operation. and that the curve D indicates the speeds at which the automatic l application of the brakes will occur when the time control device has run out.-

the exact speed and the distance will depend upon the rate of acceleration ordeceleratlon during the time elapsing from the instant the v' train exceeds the speed prescribed bythefcam curve. In this connection` the cam curve is preferably shaped such that an automatic Y `applicationof the brakes will vnever occur at a higher speed for a given point than indicated by lthe curve D, even though vehicle is accelerating during the t1m\e.1n.l

control apparatus on the vehicle :and refer# ring to Fig. 1 it can be seen that after'the cam K is connected to the Wheels, `as ,pre-

Strictly, speaking, the curve D only approximatelyv represents the speed at which the automatic application of the brakes will occur, because viously described, and commences'to turn gradually in accordance with ,the distance .traveled by the vehicle, the right hand end of the loating lever 26 will be gradually raised.

The left hand end of this vfloating lever is,

tion, corresponding to the permissive speed it is desired to enforce at that instant,-the

lefthand end of. the 'lever 26 will be' raised 'l by the' speed responsive device, provided the..

tioned that, with the cam K in a given posi- 'y actual speed of the vehicle is greaterithan i this permiss'ive speed, to a point where the` link .e5-'will ybe moved.v upward `far enough to vcause the in'sulated'piece 47 to lift the contactmember 48, thereby initiating the operas which` act to compel a reduction ijn speed of the 'vehicle'. "This action will take place retered the block and at the proper point in the block.

The raising of the contact membe'r 48 establishes a circuit for sounding the warning whistle. Forconvenience, some of the circuits have been shown as extending from one grounded point (shown conventionally) to another, with a separate battery in each circuit; but it is to be understood' that in practice ordinarily only one battery would be used, and consequently the batteries have been given the same reference character O With distinctive exponents added. Itwill be evident that these circuits which extend from one grounded .point to another grounded point are completed by the frame or body of the vehicle. The circuitfor the warning signal may be traced as follows: from ground through the battery O1, conductor 110, contact member 48, conductor 111, solenoid-l, and conductor 112 to ground.

At the same time, a normally closed circuit for energizing the winding 58 of the solenoid M is interrupted, said circuit being traced as' follows: from ground to the battery O1, conductor 110, contact member 48, conductor 114, winding 58, and conductor v115 to ground. The solenoid M beingdeenergized, its core 59 commences to move gradually downward in accordance with time. f

Upon sounding of the warning whistle W, the engineer is expected to immediately shut off the power and more his brake handle to the service position. Assuming that the en- Lgineer properly performs his duties in this way, a circuit is established for energizing the winding 57 of the solenoid M, saidcircuit being traced as follows: fromground through the battery O2, conductor 116, contact fingers c, conductor 117, contact fingers b, conductors 118' and 119, winding 57, and conductor 12() to ground. The establishing of this circuitl restores the core 59 to-its upper or normal position. In practice, it isnecessary for the `engineer to keep his brake valve inthe service position for only a short time` in order to cause aservice application of the brakes,` whereupon he may move it back to the lap position; This would open the circuit just traced at the contact lingers I). In the meantime, however.. a shunt for these contact fingers I), comprising conductors 121 and 122, is established at the Contact springs T6 by the contact piece 81, providing the brakes have properly operated and air pressure actually exists in the brake cylinder 83. In this way, although .the engineer puts his brake valve back to the lap position, the winding 57 of the solenoid M is maintained energized, so as to prevent an automatic application ofthe brakes. It the engineer should release the brakes, or attempt to move the controller handle 72 to a power position, the Winding 57 would become deenergized, and

in time an automatic application of the bra-kes would occur. Consequently, not only must the engineer observethe warning signal by vshutting off the power and actually applying the brakes, but he must maintain the brakes applied and the power off. An-

cally restore the core 59 to the upper position and reenergize the solenoid 69.

To illustrate this operation just described, referring to Fig. 5,y assume the train enters the block at the speed represented by the dot and dash line G, and after receivin the caution signal Y continues at this spec At the point 12d where this dot and dash line. G

intersects the cam curve, thecontact member 48 will be raised. If the engineer properly performs his duties, the train will continue at substantially a uniform speed, as illustrated in Fig. 5 by the dot and dash line G extending fromthe point 126 tothe point 127 horizontally, for a. distance representing the travel of the train while the engineer is shutting olf the power and applying the brakes. At or about the point 127, the brakes will be fully acting. The portion of thc dot and dash curve G just to the left of the dash line D from point 127 down represents the speed-distance curve of the train under the manual service application of the brakes.

y In this connection, it is noted that Fig. 5 and the foregoing description have been made on the assumption that as much facility as possible is desired, the cam curve and the dash curve D being caused to correspond substantially with the speed-distance curve of the train under a full service application. In other words, the curves in Fig. 5 are drawn with the idea that after the train has once exceeded its permissive speed,l the brakes must be continuall applied until the end of .the block is near y reached'. After the train has gradually reduced its speed in accordance with the dot and `dash line curve G to the point 128 where this curve intersects the cam curve, the actual speed of the train 1s then below the permissive speed, so that the contact member 48 is permitted to move to its lower position. This stops the sounding of the Warning Whistle W and advises the engineer that he has succeeded in controlling his train to a safe speed. When the warning signal W stops sounding, the engineer is expectedto release the brakes and continue at a speed slightly less than ,the minimum permissive speed, as indicated by traliic conditions 'ahead become safe, thev the lower horizontal portion of the dot and dash curve G. After having brought his train to a predetermined low speed, the engineer may bring his train to a stop at the end of the block, withthe contact shoe of the engine or first motor car of the train in engagement with the ramp R at the entrance to the next block in advance, so that when speed control relay SC will be automatically re-energizedas explained hereinafter in describing the operation of the trackway circuits, thereby reenergizing the cam control solenoid 35 and permitting the cam K to return automatically to its normal or initial maximum speed position under the iniiuence of the counterweight 42, ready for its next operation when required. This permits the engineer to accelerate without delay. If, however, conditions require, the engineer need not wait for the, speed control relay SC to be re-energized, but may enter the next block at the low minimum speed prescribed by the cam. The mutilated portion of the gear 39 provides for this continuing movement of the vehicle without causing further movement of the cam K and without injuring the parts. If, while his train is traveling through this next block at the minimum speed, the engineer should attempt to exceed this minimum speed, the warning signal would be sounded and in time an automatic application of the brakes would result unless the engineer should reduce speed. In this way, the train may be allowed to enter a block even though the ramp at the entrance to that block is in the condition indicating that the block in question is 'occupied by another train.

Assume that the engineer, after having received the warning signal, is incapacitated or through negligence or carelessness fails to promptly shut off the power and manually apply the brakes. After the lapse of the time for which the time mechanism P is set, the brakes will be automatically applied by reason of the fact that the contact disk 61 moves downward far enough to break circuit with its cooperating contacts, thereby interrupting the normally closed circuit for energizing the solenoid 69 controlling the electropneumatic brake Valve E. P. V. said circuit being traced as follows: from ground to battery O3, conductor 123, contact disk 61, conductor 124, solenoid 69, and conductor 125 to ground. Since the time interval for which the time control mechanism is set corresponds at any given speed with the distance between the cam curve and the curve D, this automatic application of the brakes takes place at about the point to cause the vehicle to decelerate along the curve D, and the speed of the train is reduced in accordance with the curve D. In this way, the train is automatically brought to a safe low speed before it reaches the end of the block, regardless of the speed at which it entered that block.

The performance of the vehicle just described is illustrated in Fig. 5 by the horizontal dot and dash line between points 127 and 129, it being assumed as before that the vehicle enters the block at the speed repre sented by the horizontal portion of the dot and dash curve G and that the engineer receives the warning signal at the point 126 and continues at the same speed without any effort to shut `olf the power or apply the brakes, the automatic application of the .brakes taking place at the point 129.

In connection with the operation of the train control apparatus described, one important feature of this invention is the pro-y vision for preventing the automatic application of the brakes by the running out of the slow acting device P when the engineer obeys the warning signal by shutting 0E the power and manually applying the brakes. This feature is of importance, because it is im-Av practicable to obtain the desired facility of train movement by depending upon the c1os ing of the circuit at the contact arm 48 to re-energize the solenoid M, so as to arrest further operation of the device P, since this would occur only after the vehicle had reduced its speed below the limiting speeds prescribed by the cam curve; and it can be seen that if this reduction in speed is to be accomplished by la manual application of the brakes after the sounding of the warning signal, the rate of deceleration indicated by the cam curve must be much less than that of the service application of the brakes. Otherwise, with the cam curve determined from the service breaking curve (as described and shown in Fig. 5) the very best reduction in speed which the engineer could accomplish by a manual application of the brakes would be indicated by the dot and dash curve G, and it can be seen that this curve does not again cross the cam curve until the lowest speed is reached. In other words, unless the cam curve is made so fiat as regards the actual service braking curve, as -to greatly lengthen the blocks beyond that required for safety, thereby seriously interferin with the train capacity, the engineer coul never in spite of his best efforts prevent an automatic application of the brakes by the running out of the device P, unless some other expedient than the reclosing of the energizing circuit of this device Pl by the cam controlled contacts is adapted to prevent an automatic a plication by the running out of the device Mami/mum speedv limitation-Even when the cam K is in its normal or initial position there is imposed a limitation on the maximum speed at which the vehicle may travel, this maximum limiting speed being determined by the radius of the cam in its normal position. This maximum speed is indicated in enAl Fig. 5 by the horizontal portion of the cam curve at the left of the point 109. This limitation upon the maximum speed of the vehicle prevents the vehicle from. entering a given block at too high a speed and may also be used to limit the speed of the vehicle over certain sections of the railroad, such as over cross-overs, around sharp corners, through yard limits, and the like.

Recording mechawsm.-The circuit for energizing the solenoid of the recording mechanism so as to make a permanent record may be traced as follows: from ground to the battery O, conductor 130, solenoid 70, conductor 131, contact disk 60, conductor 132, and thence along either of two multiple paths, one through the contact fingers a, conductor 133, to conductor 135, or yalong conductor 134 through the contact fingers d to the con'- ductor 135, thence through the contact disk 55, and conductor 136 to ground. The above traced circuit for operating the recording mechanism is normally open, and consequently any failure of a part of this circuit results in a failure to make a record rather than in making an improper record. The'operation of the recording mechanism depends: first, upon the core 59 of the solenoid M being in its lower position, second, upon either the controller handle 72 being in a power position, or the engineers brake valve in the release or running position; and finally upon the solenoid 54 being energized. When the solenoid 54 is energized, then the warning signal is sounding, and if the engineer fails to either shut on' the power or manually apply the brakes, and the brakes are automatically applied by the dropping of the core 59, a record is made against the engineer. By reason of this control of the recording mechanism, it is assured that a record will never be made unless the engineer is at fault; and when a record is made, it is possible to justly penalize the engineer; because it is positively assured that this record is not due to any failure of the train control apparatus to operate properly. If the brakes are improperly applied by the electro-pneumatic valve E. P. V., due to a failure in its circuit, a record will not be made because the circuit controlling the recorder will be broken at the contact disk 60. If the solenoid M should be improperly deenergized because of a failure 1n its circuits, no recordwould be made because the circuit operating the recorder would be broken at the contact diskv 55. If, for any reason, current is not actually applied to thel solenoid 54 controlling the warning slgnal, so that the warning signal in fact does not operate when it should, a record will not be made, because the contact disk 55 will not then close the circuit.' It will also be noted that the engineer is not required to actually slow down his train but is only required to shut off the power and move his brake valve to the brake applying position; and if he properly performs these movements a record will not be made against him. If, for any reason, the braking equipment of the train is defective, so that even though the engineer moves his brake valve to the service position, the brakes do not actually operate, the 4engineer will not have a record made against him although the time controlled device P may continue in operation and open the electro-pneumatic valve E. P. V., for the reason that the recorder circuit will be broken at the contacts a while the engineer is trylng to apply the brakes.

Tmccwag/ Garanta-From a consideration of the operation of the apparatus carried on the vehicle it can be seen that when the speed control relay SC is energized, the camK 1s 1n its maximum speed position, when this relay is deenergized the cam K is operated to 1mpose a gradually decreasing l1m1tat1on iupon the speed of the vehicle, and when this relay is reenergized, it having once been deenergized, the Cam is automatically restored to its maximum speed position. The speed control relay SC may be controlled at the proper times and in the proper way to accord with traffic conditions ahead by various arrangements of trackway circuits; and one such arrangement is illustrated in Fig 4. Referring to F ig. 4, the track rails 1 and 2 are divided by insulating joints 140 into blocks A, B and C in the usual way, only the block B being entirely shown. In this connection, it should be understood that when the invention is applied to electrically propelled roads, the usual impedance bonds will be used to render the track rails electrically continuous for the propulsion current and yet electrically isolated for signaling current. Such impedance bonds are shown diagrammatically in Fig. 4 and are designated generally 141. The circuits and apparatus associated with each block are` the same and for convenience corresponding parts and conductors are given the same reference characters with distinctive exponents added.

Each block is provided with a track relay 142 connected across the track rails at one end of the corresponding block in the usual way. Each block is also provided with a track transformer 143, the secondary 0f which is connected across the track rails in the usualy way and the primary of which is connected to a transmission line 144 which is supplied with conductors 146, relay armature 147 raised,

llo

conductor 148, secondary of transformer T, and conductor 149; Consequently, When the vehicle approaches the'block B and its contact shoe engages the ramlp RB, high voltage is supplied to the ramp R until the first pair of Wheels enters the block B. The pick up relay CP on the vehicle has one terminal connected by the conductor 150 to the contact shoe. Its other terminal is connected by conductor 151 through impedance 152 and con-- ductor 153 to the wheels and axles of the ve hicle. The impedance 152 is shuntecl by a partial circuit of low resistance when the contact linger 155 of the speed control relay SC is raised, this shunt comprising conductor 154, contact finger 155 in its raised position and conductor 156. The impedance 152 is so adj usted that when high voltage is applied to a ramp, and this impedance is in circuit with the relay CP, suiicient current will be supplied to cause the relay to raise its contact finger 157 The raising of the contact finger 157 energizes the speed control relay SC by establishing a circuit which may be traced as follows: commencing at the battery C, conductors 84 and 85,.relay. SC, conductors 86 and 158, Contact finger 157 raised, and conductors 159 and 92 back to the battery C. l/Vhen low voltage is ap lied to a ramp, if the impedance 152, is included in circuit With the relay CP, its contact linger 157 will not be raised, but if 'this impedance 152 is shunted, the Contact linger 157 will be raised. In ordertoexplain clearly the diiierent controlling efl'ects produced upon the s eed control relay SC under different tra c conditions occuring in different practice, it is convenient to explainthe operation of therelay SC under certain assumptions of traffic conditions. For ytheiirst assumed condition,

suppose that the vehicle under consideration has been traveling along the track Without being under the dominance of its speed control apparatus, except` for the maximum speed limitation, andsuppose that this vehicle approaches the block B When neither the block B nor the block C is occupied by another train. Upon engagement of the shoe of the vehicle With theramp RB, the stick circuit for the speed control relay SC \villbeinterrupted,as hereinbefore explained, but at the same time the high Voltage applied-to this ramp will cause the relay CP to raise its Contact finger 157, thereby maintaining the speed control relay SC energized independently of its stick circuitt As the vehicle progresses and its first pair of wheels enter the block B, the track relay 142 associated with this block is shunted and its contact linger 147 drops. With the block C uri- .relay SC until shoe leaves electrical Contact with the ramp RB, whereupon the stick circuit for the relay SC is established.' In this way, when the vehicle passes the entrance to a block when the next block in advance is not occupied, the speed control relay SC is maintained energized.

For the next trailic condition, assume that the vehicle approaches the block B While another train occupies the block C. Before the first pair of Wheels of the vehicle enter the block B, the same operation occurs as hereinbefore explained but when the vehicle in question enters the block lB and shunts the track relay 142, the speed control relay SC is deenergized by reason of the fact that its stick circuit is interrupted and the relay CP is deenergized, the circuit supplying low' voltage to said relay CP being interrupted at the contact iinger 1611 of the track relay 1421. In this Way, when a train entersthe block, as the block B, and the block next in advance, as the block C, is occupied by another train, the speed control rela SC on the following vehicle is deenergize and the speed control apparatus on the vehicle set yinto operation. l y

Assume that the speed control apparatus has been set into operation when the vehicle enters the block B, and that by the time this.

vehicle reaches the end of the block B, the train ahead formerly occupying the block C has moved out of that block. Then, the ramp RC Will-be supplied with high voltage since the contact linger `1471 of the track-relay'142" 'is in its upper position.l` Consequently, even though the speed control relay SC' is at that.

time deenergized and the'impedance 152 included in the circuit With'the relay CP, sufficient current is su plied to the relay .CP to raise 'its contact nger 157, thereby reenei'gizing the speed control relay SC; If the train ahead is in the block next in'i advance of the block C, upon entrance of the vehicle in question into the block C, the speed control relay SC will be .deenergized in the same way as previously explained.

Assume, however, that after the speed control apparatus on the vehicle has rbeen set into operation at the entrance to the block B due to the presence of the train ahead in the block C, that this train ahead still occupies the block C at the time the vehicle reaches the end of the block B. Under these condi! tions either low voltage or zero voltage will be applied to vthe ramp RC, depending upon iin iis

whether or not the block next in advance of the block C is occupied or unoccupied. In either case, the relay CP will not be reenergized, since the impedance 152 is then included in circuit with it and'low voltage is insufcient to raise the contact linger 157. Consequently, the following vehicle is not released frein the dominance of its speed controlapparatus, and if it enters the block C at all," it must do so at the minimum speed to which it is restricted by the cam K in its minimum permissive speed position. In this connection it will be noted that the worm gear 39 is provided with a cut away portion, so that after the cam K and the shaft 40 have rotated to the minimum speed position, further movement o'f the vehicle will not cause further rotation of the shaft 40, since the teeth of the Lworm 38 rotate idly in the Cut away portion of the worm gear 39.

In describing the combination and arrangement of parts and circuits embodying this invention, no attempt has been made to show and describe all of the various and obvious modifications, and it should be understood that the specific embodiment of my invention shown and described is susceptible of change to accord with the varying'requirements of railroads and varying; conditions. For example, it may be found desirable in some instances to omit the contacts Z on the controller L. This change would enable the motorman or engineer oi the vehicle to reverse his motors or engine in obedience to the warning signal, without having a record made against him. To illustrate, suppose that the vehicle exceeds the prescribed permissive speod and the warning whistle W is sounded. The operator of the vehicle may shut olfv his power and give a service application of the brakes, which as previously described, would energize the winding 57 of the solenoid M and prevent an automatic application of the brakes. There might be occasions, however, where the brakes would not retard the train suiiiciently, due to slippery rails or other causes, so that for the sake of safetythe operator of the vehicle should reverse his motors or en ine. This reversal would include moving t e power controller to a position sup lying power, thereby brealrl ing the circuit or energizing said winding 57, so as to permit the time controller device Pto operate and after the lapse of an interval of time apply the' brakes automatically. Gbviously the operator oi the vehicle should not be penalized in such cases, and for this reason, the contacts d, above referred to, may bev omitted or combined in circuit with auxiliary contacts connected with the reversing lever. It will be observed that the contactbon the brakvalve is closed when this brake valve is in the emergency position. This is an optional arrangement, and in some respects, greater safety might be obtained by con- Wecare structin these contacts so as to be closed only in t e service position of the brake valve. As an illustration, suppose that the brake valve for some reason should not operate properly when moved to the service position. Then, the operator of the vehicle upon receiving the warning signal and failing to obtain the desired retardation of his train by a service application of the brakes, would naturally move his brake valve to the emergency position. This would keep the contacts b still closed and prevent possible action of the electrically operated brake controlling valve E. P. V. From the standpoint of safety, however, it might be considered desirable to have this automatic brake controlling device E. P. V. operated as quickly as the time control device P would permit, since the defect preventing proper operation of the service application of the brakes might also apply to the emergency application of the brakes.

Also, no attempt has been made to illustrate and describe all of the various devices which may be essential to constitute a complete system for practical use, sincethe way in whlch these various other devices, which are disclosed in other of my a plications, may beincorporated with the iatures ofthe system herein shown and described, will be readily apparent to one skilled in the art.

onsequently, although I have particularly described the construction of one physical embodiment 'of m invention, and explained Vthe operation an principle thereof; nevertheless, I desire to have it understood that the form selected is merel illustrative, but does not exhaust the possible physical embodiments of the idea of means underlying my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

l. In an automatic train control system, the combination with' a vehicle, of automatic train control apparatustherefor adapted to be conditioned :for operation from the trackway and acting when thus conditioned to cause automatic application of the brakes of the vehicle whenever it thereafter exceeds certain prescribed limiting s eeds during its progress along the track, trac ay means for conditioning and restoring said apparatus, a warning signal adapted to attract the attention of the operator of the vehicle and operated prior to the automatic application of the brakes, and means acting when the brakes of the vehicle have been applied manually by the operator of the vehicle for preventing such automatic brake application by the action oi said apparatus.

2. `In an automatic train control system, the combination with e. vehicle, of automatic train control apparatus therefor adapted to cause an automatic application of the brakes whenever the vehicle exceeds certain prescribed limiting speeds during its progress lOO vehicle and given prior to the automatic application of the brakes, power and brake control devices for the vehicle adapted to be 'actuated manually by the operator, and means dependent upon said `control devices being in position to retard the movement of the vehicle for preventing the automatic application of the brakes by the action of said apparatus.

3. In an automatic train control system, the combination with a vehicle, of automatic train control apparatus therefor comprising means adapted to prescribe limiting speeds for the vehicle during its progress along the track, a slow acting device having a tendency to assume an active condition and governed by said apparatus, said device being set into operation when the vehicle exceeds the limiting speed prescribedl therefor, means controlled by said slow acting device' for automatically applying the brakes of the vehicle after an interval of delay, a warnin signal arranged to attract the attention of t e operator of the vehicle andsimultaneously operated automatically when said slow acting device is set into operation, and automatic means for preventing the automatic application of the brakes 'by the action of said .slow acting device when the brakes of the vehicle are applied manually by the operator in obedience to the warning signal.

4. In anautomatic train control system, the combination with a vehicle, of automatic train control apparatus therefor comprising meansv adapted to prescribe limiting speeds for the vehiclev during its progress along the Y track, a warning'signal in the cab, a normally energized brake setting appliance, means tending to assume its active condition and governed by said train control apparatus for operating the warning signal when the vehicle exceeds the prescribed limiting speed and for operating the brake setting appliance after an interval of delay, control devices adapted to be operated manually by the operator of the vehicle to retard its movement,

a and means dependent .upon said control devices. being operated to cause retardation of the vehicle for preventing said automatic application of the brakes.

5. In an automatic train control system,

the combination with a vehicle, of a warnl ing signal arranged to attract the attention of the operator of the vehicle, a slow acting device,l a brake settingappliance operated when said slow acting device attains its ultimate condition, automatic train control apparatus for simultaneously giving the warning signal and setting said slow acting `device into operation when the vehicle exceeds certain prescribed limiting speeds during its travel, and means for restoring said slow acting device to. its initial condition when the brakes of the vehicle are acting.

6. In an automatic train control system, the combination with a vehicle, of automatic train control apparatus therefor comprising a normally energized slow acting device having a tendency to assume its active condition and adapted when set into operation to cause an automatic ap lication of the brakes after an interval of elay, a warning signal arranged to attract the attention of the operator of the vehicle and operated at the'same time said slow acting device is set into operation, and means adapted to be controlled manually by the operator of the vehicle for preventing such-automatic application of the brakes by the action of said slow action device. 4

7. In an automatic train control system, the combination `with a vehicle, of a slow acting device thereon having a tendency to assume an ultimate condition and cause an automatic application of the brakes of the vehicle after an interval of delay, means for normally maintaining said slow acting device in its initial condition, 'a warning s1gnal on the vehicle, means responsive to the speed of the vehicle and its-location along the track for simultaneously givin the warning signal and controlling sai means to set the slow acting device into operation, and means on the vehicle adapted to be operated manually by the operator thereof for preventing 'said slow acting device from attaining its on the vehicle arranged to attract the attention of the .operator thereof, a brakesetting appliance, slow acting means adapted when set into operation to cause actuation of said brake setting appliance a't'ter an interval of delay, means responding jointly to said permissive speed device andsaid speed responsive devlce for simultaneously giving the 'warning slgnal vand settingsaid slow acting means into operation wheneverv the actual speed of the vehicle exceeds the prescribed permissive speed and means adapted to be operated manually by the operator for preventing the actuation of the brake setting appliance when the operator acts in obedience to said warning signal.

9. In an automatic train control system, the combination with automatic train control yapparatus on a Avehicle comprising normally energized devices tending to assume an active condition in which the brakes oit' the vehicle are automatically applied, said apparatus including a normally deenergized warning sig- Y ,said automatic train control apparatus acts nal and means for causin operation of said warning signal prior to the automatic brake application, of an electrically operable recorder, a normall open circuit for operating the recorder, an means dependent jointly on the operation of the warning signal and said devices causing an ,automatic brake application for closing said circuit, whereby the recorder will not be operated by accidental failure of the said normally energized devices.

10. In an automatic train control system the combination with a vehicle, of automatic train control apparatus therefor comprising devices having a tendency to assume an active condition and adapted to automatically apply the brakes of the vehicle whenever it exceeds certain prescribed limiting speeds during its progress along the track, a recorder, control means adapted to be operated manually by the operator of the vehicle for governing the movement thereof, and a normally open circuit for actuating the recorder which includes in series circuit controllers which are separately closed when t'o apply the brakes and said control means is in position permitting unretarded movement of the vehicle.

11. In an automatic train control system, the combination with a vehicle, of automatic train control apparatus therefor adapted to give a warnin signal and then automatically apply the bra es after an interval of delay when the vehicle exceeds certain limiting speeds during its progress along the track, a recorder, control means on the vehicle adapted to be actuated manually by the operator for governing the movement of the vehicle, and means for actuatin 1 the recorder, and a. normally open circuit or actuating the recorder, said circuit including in series three circuit controllers which are closed respectively when the warning signal is given, the brakes are automatically applied, and said control means are in position permitting unretarded movement of the vehicle.

12. ,In an automatic train control system, the combination with la vehicle, of slow acting means adapted to cause an automatic application of the brakes vof the vehicle after an interval of delay, automatic train control apparatus for setting said slow acting means into operation, braking equipment for the vehicle including a brake cylinder, and means effective when pressure exists in said brake cylinder for preventing operation of said s ow acting means.

13. ln an automatic train control system, the combination with train control apparatus on a vehicle comprising a warning signal adapted to attract the attention of the-'operator, time-controlled means for automatically applying the brakes at the expiration off a predetermined time followingthe inltiation of its operation, and means for simultaneousmea-ara ly actuating the warning signal and initiating the operation of said time-controlled means, of means operable manually by the operator for rendering said time-controlled means inactive and thereby preventing an automatic brake application.

14. Automatic train control apparatus fork applying position for maintaining said de vice energized.

16. Automatic train control apparatus for railway vehicles comprising,- in combination: an electrically operated brake setting appli'- ance, a centrifuge driven by the wheels of the vehicle and responsive to the s eed of the vehicle for maintaining said app iance normally energized, and a normally open auxiliary energizing circuit for said appliance,

and normally open contacts in said circuit closed when the brakes` of the vehicle are acting.

17; In an automatic train control system, train control means on a vehicle governed fromy the trackway in accordance with trafiic conditions, and adapted to cause an automatic brake ap lication when operated, power con trol and rake control devices manually operable b the operator of the vehicle, and means e ective while saidv devices are in the `power off position and brake applying position respectively for preventing such brake applicationby the operation of said train control means independently of its control from the trackway.

18. In iin-automatic train control system for railway vehicles, the combination with speed control apparatus on avehicle adapted when set into operation to enforce decreasing limitations upon the speed of said vehicle, said apparatus including a brake setting appliance, of means whereby the operator of the vehicle may prevent such automatic brake application by shutting o the power and manually applying the brakes.

19. Train control equipment 'for railway vehicles comprising, in combination: a

power controller, an engineers brake lvalve, l

pairs of contacts controlled by the power controller and the engineers brake valve and closed when they are in positions corresponding respectively to power o' and y brakes applied,l automatic train control means for the vehicle including a normally inactive brake setting appliance, and a circuit including -said pairs of contacts in multiple for maintaining said appliance inactive.

20. ln an automatic train control system for railroads, having tracks divided into blocks each provided with a normally closed track circuit, train control apparatus on a vehicle normally tending to assume its active condition and including a brake setting appliance operated when the speed of the vehicle is excessive, traliic controlled impulse transmitting means partly on the vehicle and partly along the track for rendering said train control apparatus active near the entrance to a block when the next block in advance is occupied, and for restoring said appara-tus to normal at the end of the block when said next block in advance is not occupied, and means effective while the brakes of the vehicle are acting for maintaining said brake setting appliance in its normal condition independently of the control thereof by said apparatus.

2l. Automatic train control equipment for railway vehicles comprising, train control means for automatically applying the brakes of the vehicle dependent upon traliic conditions, an engineers brake valve, a recorder, and means acting to operate said recorder when said train control means acts to apply the brakes and the engineers brake valve is in its normal running position, whereby a record is made when the engineer fails to apply the brakes.

22. Automatic train control equipment for railway vehicles comprising, a power controller7 an engineers brake valve, trafiic controlled means for ap lying the brakes automatically if the englneer fails to shut off power and operate his brake valve to apply `the brakes, a recorder, and means governed by said trac controlled means and also dependen-t upon the position of the power controller and the engineers brake valve for actuating said recorder.

23. Automatic train control equipment for railway vehicles comprising, a power controller, an engineers brake valve, an

electrically operable recorder, pairs of con-- tacts closed when the power controller and engineers brake valve are in position corresponding to power on' and brakes oli", and a controlling circuit for the recorder including said pairs of contacts in multiple. y

24. Automatic train control equipment for railway vehicles comprising, slow-acting means adapted to apply the brakes of the vehicle, traiic controlled means for governing said slow-acting means, manually operable means under the control of the operator for maintaining said slow-acting means in its normal condition, and a recorder having its operation controlled jointly by said manually operable means and said slow-acting means.

25. Automatic train control equipment for railway vehicles comprising, train control apparatus including normally energized devices having a tendency to apply the brakes of the vehicle and control means therefor, a normally deenergized magnet, said control means acting to energize said ma et at the same time it deenergizes said devices, and a recorder controlled by said magnet and said devices and operated when .all have assumed their active condition, whereby no record will be made by accidental failure of one of the normally energized devices.

26. Automatic train control equipment for railway vehicles comprising, train control apparatus including a primary control device, normally open and normally closed contacts simultaneously actuated when said train control devi is operated, biased brake control means governed by the normally closed contacts, an electrically operable recorder, a normally open circuit for actuating said recorder, and separated means dependent respectivelyupon the operation of'said brake control means and said normally o-pen contacts for governing said recorder circuit, whereby no record will be made by an accidental failure of the brake control means.

27. Automatic train control equipment for railway vehicles comprising, speed control apparatus on the vehicle including permissive speed means and a speed responsive device governed in accordance with the actual speed of the vehicle, circuit controlling means governed by said apparatus and including normally open contacts and normally closed' contacts operated simultaneously, biased brake control means governed by said normally closed contacts, and a recorder having its operation dependent upon the operation of said brake control means and the closing of said normally open contacts, whereby accidental failure of said brake control means will not make a record.

28. Automatic train control apparatus' for railway vehicles comprising a normally energized electrically operable time-controlled device adapted when set into operation to cause an automatic brake application after the lapse of a predetermined time, a warning signal arranged to attract the attention of the operator, and means having its operation dependent on the speed of the vehicle for simultaneously actuating the warning signal and setting said time-controlled deviceinto operation.

29. Automatic train control apparatus for railway vehicles comprising a time-controlled device having a tendency to assume an ultimate condition, 'a brake settingappliance actuated when said device attains such ultimate condition, a warning signal, and per- `llO missive speed means and actual speed means cooperating to operate the Warning signal and simultaneously initiate the operation of the time-controlled device when the vehicle exceeds predetermined limiting speeds.

30. In a train control system for railroads having tracks divided into blocks, the combination with tratlic controlled trackvvay means, of speed control apparatus on a. vehicle including changeable permissive speed means conditioned for operation by said trackway means near the entrance to a block when the next block in advance is occupied, actual speed means, said apparatus comprising a time-controlled device electrically controlled by the cooperation of said permissive speed means and said actual speed means, a

brake setting appliance operated by the timecontrolled device after the lapse of a. predetermined time, and a Warning signal actuated when the operation of said time-controlled device is initiated.

3l. In a train control system for railroads having tracks divided into blocks, the combination with t-ratiic controlled trackway means, of car-carried apparatus conditioned for operation by said trackway means in a block in the rear of an occupied block, said apparatus comprising a time element device tending to assume an ultimate condition, a brake setting appliance operated by said device when it attains its ultimate condition, a warning signal, and speed-responsive means cooperating with permissive speed means to simultaneously actuate the warning signal and initiate the operation of said time element device.

32. In an automatic train control system, car apparatus comprising a Warning signal and an electrically operated slow-acting device adapted to cause an automatic brake application after an interval of time, said apparatus when conditioned for operation continuing in operation until restored and acting While in operation to actuate the Warning signal and simultaneousl initiate the operation of said slow-acting evice dependent upon the speed of the car, and means partly on the car and partly on the track for conditioning and restoring said apparatus in accordance with traitic conditions in advance.

3o. In an automatic train control system, apparatuson a vehicle adapted When conditioned for operation to enforce a reduction in speed to a predetermined minimum and to maintain that minimum speed limit until the apparat-us is restored, said apparatus comprising an electro-responsive time-controlled device governing the brakes of the vehicle and a'ivarning signal actuated when the timecontrolled device is set into operation, and traclrway means for conditioning and restoring said apparatus in accordance with traiiic conditions.

34. Automatic train control apparatus for meeste railway vehicles comprising, an electromagnet,'acircuit for normally maintaining said magnet energized, means'governed 1n accordance-With traiic conditions for interbraking system for closing said auxiliary circuit Whenthe brakes are actually applied.

35. Automatic train control apparatus for railway vehicles comprising a normally energized electrically operable brake setting appliance adapted 'when deenergized to cause an automatic brake application, apparatus including a speed-responsive device driven from the Wheels of the vehicle for governing said appliance, and means acting to maintain the brake setting appliance energized independently of its control by said apparatus when the brakes of the vehicle are acting.

36. In a train control system,;the combination With apparatus on a vehicle for automatically Aapplying the brakes thereof, of means associated with the brake equipment of the vehicle and including biased circuit controlling means actuated by pressure as the brakes are applied or released, and a circuit governed by said means for preventing operation of said apparatus to apply the brakes.

37. A train control system for railroads having tracks divided into blocks, comprising automatic apparatus on a vehicle including a permissive speed device driven from the Wheels of the Vehicle and an actual speed device driven from the Wheels of the vehicle and adapted when set into operation to apply the brakes of the vehicle automatically when it exceeds predetermined limiting speeds during its .progress through a block, means partly on the vehicle and partly along the track for setting said apparatus into operation near the entrance to a block when the next block in advance is occupied, and means associated with the brake equipment of the vehicle and acting when the brakes are applied to prevent an automatic brake application by the operation of said apparatus.

38. In a train control system according to claim 37, speed control apparatus comprising a permissive speed device and adapted when set into operation to continue the operation until restored, together with means partly on the track and partly on the vehicle or restoring said apparatus at the end oit each block when the next block in advance is not occupied.

39. In a train control system, traliic controlled trackway means, ycar equipment comprising a circuit, means controlled by said trackvvay means for opening and closing said circuit as the car exceeds or falls below predetermined speed limits during its progress, slow acting means set into operation by the opening of said circuit and acting to automatically apply the brakes after an interval vehicles comprising, a brake control electromagnet, a circuit for normally maintaining said magnet energized, speed responsive means driven from the wheels of the vehicle for causing interruptionof said circuit, and

means for preventing deenergization of said electro-magnet while the brakes of the train are applied due toa manual application of the brakes.

l 42. In combination, a railway vehicle provided with a braking system,.automatic apparatus for causing an automatic application of the brakes when said vehicle exceeds certain prescribed limit speeds during its progtus, said means being effective only when the brakes have been applied manually by the operator of the vehicle.

43. In combination, a railway vehicle provided with a braking system including a manually operable control device for causing a brake application, automatic apparatus for -causing automatic application of the brakes when said vehicle exceeds certain prescribed limit speeds during its progress along the track, and means responsiveonly to an actual application of the brakes by operation of said cont-rol device for preventing operation of said automatic apparatus. 44. In combination, a railway vehicle provided with a braking system, automatic apparatus for causing an automatic application of the brakes upon a prescribed change in traffic conditions if the speed of the vehicle exceeds a prescribed value, and manually yoperable means for preventing such automatic application of the brakes, said means being effective only when thebrakes have been applied manually by the operator of the vehicle.

45. An automatic train control apparatus, comprising brake control mechanism, electrically operable automatic means for actuating said mechanism, a circuit adapted when closed to prevent said automatic means from being actuated, and pressure responsive means for closing a break in 'said circuit when the brakes are manually applied.

46. Automatic train control equipment for railway vehicles comprising a normally energized electrically operable brake-setting appliance adapted when deenergized to cause an automatic brake application, apparatus including a speed responsive device driven from the wheels of the vehicle for governing said appliance, and means acting to maintain ,the brake-setting appliance energized vindependently of its control by said apparatus when the brakes ofthe vehicle are acting.

47. In combination, a railway vehicle provided with a braking system, automatic apparatus for causing-an automatic application of the brakes when said vehicle exceeds certain prescribed limit speeds during its progress along the track, governing means under the control of tli-e operator for governingtlie speed of the vehicle, and means dependent upon the operation of said governing means to a degree suliicient to cause retardation ofthe vehicle for preventing operation of said automatic apparatus.

48. In combination, a railway vehicle provided with a braking system including a manually operable control device for causing a brake application, automati: apparatus yfor causing automatic application of the brakes when said vehicle exceeds certain prescribed limit speeds during its progress along the track, and means dependent up'on a brake'application'of predetermined value -by the action of said manually operable control device for preventing operation of said automatic apparatus.

49. In combination, a railway' vehicle provided with a braking system including a manually operable brake control device, automatic means for causing an application of the brakes, and means for preventing operation of said automatic means while said brake control device is in brake-applying position and for continuing to prevent operation of said automatic means after said device is subsequently restored away from brake-applying position if and While a brake application of predetermined value is in effect dile to operation of said device.r

50. In combination, a railway vehicle provided with a braking system including a manually operable device, for causing application of the brakes,'automatic apparatus for also causing application of the brakes under certain tratiic conditions, and -means for preventing operation of said automatic apparatus While said device is in position to initiate a brake application and also after. said device has been restored away from initiating position if and while a brake application of atleast predetermined value is in eiect due to said device having been in initiating position.

51. Iii combination, a railway vehicle provided with a braking system, means on the vehicle for vestablishing several permissive speeds, speed responsive means on the vehilimit.

plat-automatic apparatus controlled jointlyv by said` two means for causing an apphcatioiig,` of the brakes if the actual-speed exceeds the permissive speed at any given linstant, and means for preventing operation of said alitomatic apparatus, said means being ie'ctive only when the brakes have 'been appliedby,

the operator of the vehicle to causesretardation of the vehicle. l 52. In combination, a railway vehicle'provided with a braking system including .a manually operable brake valve, automaticl means for stopping the vehicle ifcertain prescribed limit speeds are exceededby said vehicle in its progress along the track, and' means controlled by said manuall operable valve and effective onl if the'vav'ekis held in brake applying position long "enough to actually apply the brakes, fo`r preventing said action of said automatic means.-

53. Railway traiiic controlling apparatus comprising means on a train controlled from the trackway for imposing a continuously .effective speed limit under' one given condithe train, applying the brakes automaticallyA if the established speed limit is exceeded at any moment, and preventing such automatic application if the engineer takes suitable action prior to exceeding the established speed 55. The method of' controlling railway traflic which consists in establishing a continuously effective speed limit on'a train determined by trailic conditions in advancev of the train, applying the brakes automatically if `the establishedspeed limit is exceeded'at any moment, and preventing such automatic application if the engineer applies `the brakes manually prior'to exceeding the ves-l tablished speed limit and keeps them applied as long as the speed limit is exceeded.

56. In an automatic train control system,

the combination with an air brake system on the vehicle including an' engineers brake valve having a brake applying and a `lap p osition, automatic brake control means on the vehicle governed in accordance with trafic conditionsvfor applying the brakes of said air brake system, means responsive to the braking of the vehicle for-.preventing said automatic brake control means applying the brakes when the prakes are already applied, and means effec ive to prevent said autovmatic brake control means applying the brakes Whensaid engineers brake valve is 1n the brake applying position,- whereby the en gineers brake va vemay be moved to the lap position when the brakes have been manually applied without rendering saidautomatic brake control means effective to apply j the brakes.

' 57. automatic train control s stem comprising, a'vehicle equip ed wit air brakes and including a suita le engineers brake valvefor applying the brakes, an electrically operated brake control valve, a circuit for maintaining said brake control valve energized and inactive, means for controlling said circuit in `accordance with traffic conditions ahead, and an `auxiliary energiz-f ing circuit for said electrically operated brake control valve including a pneumaticall operated contact closed only when the bra res are actuallyapplied. g

58. lAutomatic. train control apparatus for railway vehicles comprising a normally energized 4electrically operable brake setting "appliance adapted when deenergized to cause an automatic brake application, an engineersbrake valve, means for controlling said appliance in accordance with traiiic conditions in advance, and two independent de i vices for maintaining said appliance energized irrespective of traffic conditions ahead one of which is controlled by said engineers brake valve and the other ofwhich is eiiective if an automatic brake application has already taken place.

. WINTHROP K. .HOVVE 

